Democrats plan to turn out thousands of African-American voters this fall, in an effort to hold the Senate majority. The challenge is that some of them aren’t yet registered to vote.

Which begs the question, after opportunities to elect and re-elect the first black president, why would an African-American choose this year’s midterm elections to finally jump from the sidelines and into the game?

This question especially matters given that contests in North Carolina, Georgia, Arkansas, Michigan and Louisiana will help determine control of the Senate.

Democratic strategists believe there is low-hanging fruit in the black populations in Arkansas and Louisiana, where Democrats are defending seats, because those states never saw a well-financed and organized get-out-the-vote effort from President Barack Obama's campaign. After all, neither state was regarded as competitive in the past two presidential races.

This cycle, Democrats on the House and Senate sides are investing unprecedented amounts of money into their party’s ground game for the midterm elections. The Democratic Senatorial Campaign Committee is set to spend $60 million on 4,000 staff in top states through the Bannock Street Project to get out the vote.

Part of that effort is focused on boosting black turnout from traditional midterm levels to something closer to presidential levels in Arkansas and Louisiana, as well as one of the Democrats' best pickup opportunities in Georgia, and potentially Michigan and North Carolina — both of which saw plenty of attention in 2008 and 2012.

Democrats are encouraged by the Obama campaign’s ability to boost the black percentage of the vote in Ohio from 11 percent in 2008 to 15 percent in 2012 . (Interestingly, the 2010 exit poll in Ohio found blacks constituting 15 percent of the state electorate in that midterm, two years before the Democrats’ major effort in the Buckeye State.)

But it’s one thing to boost African-American turnout in a year when the first black president is seeking re-election, and it is something very different to boost that same turnout during a midterm.

One of the biggest challenges facing Democrats this cycle is enthusiasm. Dan Balz had a good piece on this in The Washington Post after the special election in Florida’s 13th District.

And the African-American community is not immune from the enthusiasm challenge. Democratic strategists aren’t eager to reveal the specific messages they will use to mobilize black voters, but they are likely to try to rally those potential voters around the president and his legislative agenda, including issues of equality and fairness, such as a minimum wage increase, equal pay for women and an immigration overhaul.

Complicating the task is that Democratic strategists will be asking these new black voters to support vulnerable Democratic senators such as Mary L. Landrieu, Mark Pryor and candidates such as Michelle Nunn, each of who must demonstrate a level of independence from Obama’s agenda in order to remain competitive with white voters.

Even if Democrats succeed in registering and turning out more black voters, they will only affect total turnout in those contests at the margins. Of course, in razor thin margins, that could be enough to matter.

In Arkansas, Democrats estimate that there are 121,000 unregistered African-Americans by using census data. By registering a fraction of that population (even somewhere between 10 percent and 30 percent), Democratic strategists believe it could tilt the outcome of the race between Pryor and GOP Rep. Tom Cotton.

The black population of Arkansas is 15 percent. In the 2008 presidential election, black voters made up 12 percent of the electorate, according to exit polls. In the 2010 midterms, black voters made up 11 percent of the electorate. Because the media consortium chose to cut back its exit polling operation, there is no exit poll data for Arkansas for 2012.

Of the top 14 Senate races, Arkansas is one of seven states where the black population cracks double digits. The other states include Louisiana (32 percent), North Carolina (21 percent), Michigan (14 percent), Virginia (19 percent) and Georgia (30 percent).

The other half of the Senate playing field includes states with miniscule black populations. Those states include Alaska (3 percent), Colorado (4 percent), Iowa (3 percent), New Hampshire (1 percent), West Virginia (3 percent), South Dakota (1 percent) and Montana (less than 1 percent).

In Georgia, Democrats are excited about the long-term demographic trends in the state, but strategists believe there is a short-term opportunity to increase black turnout this year. There are an estimated 375,000 African-American voters who voted in 2012 but not 2010, and 572,000 African-Americans still unregistered. And in Louisiana, where Landrieu is running for re-election, Democrats estimate 185,000 African-Americans voted in 2012 but not 2010, and another 228,000 African-Americans are unregistered.

The New York Times did a nice piece on the relationship between the Landrieu family and black voters going back to the senator’s father and up to her brother’s recent mayoral election in New Orleans.

In 2008, black voters made up 29 percent of the vote in the senator’s re-election race, according to the exit poll . Landrieu won the black vote, 96 percent to 2 percent but lost the white vote to Republican John Kennedy 65 percent to 33 percent in her 52 percent statewide victory. Two years later in the midterm, the black percentage of the electorate slipped to 24 percent.

Theoretically there is also an opportunity to increase black turnout in Michigan. The Obama campaign was able to increase black turnout from 12 percent in 2008 to 16 percent in 2012, and there are an estimated 304,000 unregistered African-Americans in the state. But in midterms, black voters have made up closer to 10 percent of the electorate, according to pollsters who have worked in the state.

Considering long-term historical trends, increasing African-American turnout in a midterm election looks like a long shot or bank shot for Democrats. But for their strategists and campaigns, having a plan and being proactive sounds much better than simply waiting on the shore to be hit by a wave.